Methods of forming silicon-containing dielectric materials and semiconductor device structures, and related semiconductor device structures

ABSTRACT

A method of forming a silicon-containing dielectric material. The method includes forming a plasma comprising nitrogen radicals, absorbing the nitrogen radicals onto a substrate, and exposing the substrate to a silicon-containing precursor in a non-plasma environment to form monolayers of a silicon-containing dielectric material on the substrate. Additional methods are also described, as are semiconductor device structures including the silicon-containing dielectric material and methods of forming the semiconductor device structures.

TECHNICAL FIELD

Embodiments of the disclosure relate to the field of semiconductordevice design and fabrication. More specifically, embodiments of thedisclosure relate to methods of forming silicon-containing dielectricmaterials by atomic layer deposition (ALD)-type processes, and torelated semiconductor device structures and methods of forming thesemiconductor device structures.

BACKGROUND

Silicon nitride (SiN), silicon carbon nitride (SiCN_(y)), silicon oxide(SiO_(x)), and silicon carbon oxide (SiCO_(x)) are known in thesemiconductor art as dielectric materials. These dielectric materialsare fainted by various techniques including chemical vapor deposition(CVD) or atomic layer deposition (ALD). As semiconductor devices getsmaller with high aspect ratio features, often including sensitivematerials, conventional CVD and ALD processes are no longer suitable forforming these dielectric materials. In addition, ALD processes are slowand do not form a desired thickness of the dielectric material at asufficient rate. Also, when these dielectric materials are formed by anALD process that uses ammonia or an amine as a precursor, by-productsinclude hydrogen and partially fragmented ammonia or amines, whichdegrade exposed components of a semiconductor device structure on whichthe dielectric material is formed. In addition, conventional ALDprocesses are conducted at a temperature that may damage already-formedcomponents on the semiconductor device structure.

It would be desirable to have improved methods of formingsilicon-containing dielectric materials by ALD, such that good quality,conformality, and electrical properties are achieved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-5 are partial cross-sectional views illustrating differentprocess stages of a method of forming a silicon-containing dielectricmaterial in accordance with an embodiment of the present disclosure;

FIGS. 6 and 7 are partial cross-sectional views illustrating differentprocess stages of a method of forming a semiconductor device structureincluding the silicon-containing dielectric material in accordance withan embodiment of the present disclosure.

DETAILED DESCRIPTION

Methods of forming a silicon-containing dielectric material aredisclosed, as are related semiconductor device structures includingthese materials and methods of forming the semiconductor devicestructures. The silicon-containing dielectric material may include asilicon oxide material or a silicon nitride material, either of whichmaterial may also include carbon. The silicon-containing dielectricmaterial may include a silicon oxide (SiO_(x)) material, a siliconnitride (SiN_(y)) material, a silicon carbon nitride (SiC_(x)N_(y))material, or a silicon carbon oxide (SiC_(x)O_(y)) material, where x andy is each an integer greater than or equal to 1. The silicon-containingdielectric material may be a stoichiometric material or anon-stoichiometric material. The silicon-containing dielectric materialmay be formed on a substrate by an atomic layer deposition (ALD)-typeprocess. By utilizing a plasma during a portion of the ALD process, thesilicon-containing dielectric material may be formed at a lowtemperature, such as at a temperature less than about 320° C., such asless than about 300° C. or between about room temperature (from about20° C. to about 25° C.) and about 200° C. In one embodiment, the plasmais free of ammonia or an amine, yet still achieves the formation of thesilicon-containing dielectric material. The formation of the remainingportion of the silicon-containing dielectric material may be conductedin the absence of the plasma but in the same tool. Thus, a plasmaenhanced ALD (PEALD) process of forming the silicon-containingdielectric material is disclosed.

One advantage of the PEALD process includes forming thesilicon-containing dielectric material having excellent step coverageand conformity. The silicon-containing dielectric material may also beformed at a reasonable throughput and have low particle and defectlevels. In addition, the use of conventional oxidizing agents may beavoided as a portion of the process is conducted using the plasma,enabling the use of a nitrogen radical source as a nitrogen source.

The following description provides specific details, such as materialtypes, material thicknesses, and processing conditions in order toprovide a thorough description of embodiments of the disclosure.However, a person of ordinary skill in the art will understand that theembodiments of the disclosure may be practiced without employing thesespecific details. Indeed, the embodiments of the disclosure may bepracticed in conjunction with conventional fabrication techniquesemployed in the industry. In addition, the description provided hereindoes not form a complete process flow for forming a semiconductor devicestructure, and each of the semiconductor device structures describedbelow do not form a complete semiconductor device. Only those processacts and structures necessary to understand the embodiments of thedisclosure are described in detail below. Additional acts to form acomplete semiconductor device may be performed by conventionalfabrication techniques. Also note, any drawings accompanying the presentapplication are for illustrative purposes only, and are thus not drawnto scale. Additionally, elements common between figures may retain thesame numerical designation.

As used herein, the singular forms “a,” “an,” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise.

As used herein, relational terms, such as “first,” “second,” “top,”“bottom,” “upper,” “lower,” “over,” “under,” etc., are used for clarityand convenience in understanding the disclosure and accompanyingdrawings and do not connote or depend on any specific preference,orientation, or order, except where the context clearly indicatesotherwise.

As used herein, the term “substantially,” in reference to a givenparameter, property, or condition, means to a degree that one ofordinary skill in the art would understand that the given parameter,property, or condition is met with a small degree of variance, such aswithin acceptable manufacturing tolerances.

As used herein, the term “substrate” means and includes a foundationmaterial or construction upon which components, such as those within asemiconductor device structure are formed. The substrate may be asemiconductor substrate, a base semiconductor material on a supportingstructure, a metal electrode, or a semiconductor substrate having one ormore materials, structures, or regions formed thereon. The substrate maybe a conventional silicon substrate or other bulk substrate including asemiconductive material. As used herein, the term “bulk substrate” meansand includes not only silicon wafers, but also silicon-on-insulator(“SOI”) substrates, such as silicon-on-sapphire (“SOS”) substrates orsilicon-on-glass (“SOG”) substrates, epitaxial layers of silicon on abase semiconductor foundation, or other semiconductor or optoelectronicmaterials, such as silicon-germanium (Si_(1-x)Ge_(x), where x is, forexample, a mole fraction between 0.2 and 0.8), germanium (Ge), galliumarsenide (GaAs), gallium nitride (GaN), or indium phosphide (InP), amongothers. Furthermore, when reference is made to a “substrate” in thefollowing description, previous process stages may have been utilized toform materials, regions, or junctions in or on the base semiconductorstructure or foundation.

As shown in FIG. 1, the method may include placing a substrate 2 on aheater 4 in a reactor (not shown). A chamber of the reactor may bepurged using a purge gas 6 before producing the plasma. The purge may beconducted for an amount of time ranging from about 1 second to about 50seconds. However, for temperature sensitive materials, the purge timemay be reduced. During the purge, a pressure within the chamber may bedecreased, such as to a pressure of less than about 1 Torr, such asabout 0.2 Torr. Reactants (a nitrogen radical precursor, anoxygen-containing precursor (if present), a silicon-containingprecursor, a carbon-containing precursor (if present), or arate-enhancing gas, as described in more detail below) may be providedinto the chamber in gaseous form to produce a plasma from a portion ofthe reactants. The chamber may be a conventional CVD reactor, such as aPECVD reactor. By way of example, an Applied Materials PRODUCER® reactormay be used. However, other reactors may also be used. The reactor maybe configured to hold a single substrate or multiple substrates,depending on the desired throughput of the process.

After purging the chamber, the substrate 2 may be exposed to energy 8 toproduce a plasma 10 that includes excited nitrogen species, as shown inFIG. 2. A nitrogen radical precursor in gaseous form may be dissociatedinto the excited nitrogen species (e.g., nitrogen radicals (NO)) toproduce the plasma 10. The nitrogen radical precursor may include, butis not limited to, elemental nitrogen, nitrous oxide (N₂O), ammonia,nitrogen oxide, azide, an azide derivative, dinitrogen pentoxide,hydrazine, a hydrazine derivative, or combinations thereof Ammonia maybe used as the nitrogen radical precursor if underlying materials arenot damaged by hydrogen, which would be produced during the plasmaportion of the process. In one embodiment, the nitrogen radicalprecursor is elemental nitrogen. While embodiments herein describe thenitrogen radical precursor as elemental nitrogen, the nitrogen radicalprecursor may be one of the other chemical compounds previouslydescribed. When sufficient energy 8 is applied to the elementalnitrogen, the elemental nitrogen may dissociate into the nitrogenradicals. The plasma process may be initiated as the substrate 2 isheated to its desired temperature rather than waiting for thetemperature of the substrate 2 to stabilize, which may prevent damage tothe substrate 2 caused by evaporation of the reactants. The substrate 2may be exposed to the plasma 10 while the substrate 2 is coming totemperature, enabling monolayers of silicon, nitrogen, carbon (ifpresent), and oxygen (if present) to be formed before the substrate 2reaches a temperature at which existing materials on the substrate 2degrade. Thus, any already-formed materials or exposed materials on thesubstrate 2 may be sealed with the forming silicon-containing dielectricmaterial as the substrate 2 heats up, which prevents thermalout-gassing, diffusion, or evaporation of the already-formed materials.Thus, the already-formed materials may not evaporate or be damagedduring the formation of the silicon-containing dielectric material.

The plasma 10 is produced by exposing the elemental nitrogen tosufficient energy to excite the elemental nitrogen and form the nitrogenradicals. The plasma 10 may be formed by subjecting the elementalnitrogen to a plasma power between about 40 Watts and about 2500 Watts,such as between about 100 Watts and about 1000 Watts. The plasma 10 maybe a capacitive, inductive, or microwave plasma. The substrate 2 may beexposed to the plasma 10 for an amount of time ranging from about 1second to about 200 seconds, such as from about 1 second to about 100seconds, or from about 5 seconds to about 20 seconds. Other conditionsfor generating and maintaining the plasma 10 (e.g., temperature,pressure, flow rate) may be selected based on at least one of a desiredconcentration of nitrogen and oxygen (if present) in thesilicon-containing dielectric material.

A rate-enhancing gas may, optionally, be present in the plasma 10. Therate-enhancing gas may be introduced with the nitrogen radicalprecursor. The nitrogen radical precursor and the rate-enhancing gas (ifpresent) may be introduced into the chamber in gaseous form. Therate-enhancing gas may be substantially non-reactive and have a highthermal conductivity, sufficient to dissociate the nitrogen radicalprecursor into the nitrogen radicals upon exposure to the energy 8provided to form the plasma 10. The rate-enhancing gas may be a noblegas including, but not limited to, helium, neon, argon, krypton, xenon,or radon. In one embodiment, the rate-enhancing gas is helium. Whenexposed to the energy 8, the helium may form metastable helium atoms(He*), which have sufficiently high thermal conductivity to dissociatethe nitrogen radical precursor into nitrogen radicals. The energy of theexcited helium atoms may be transferred to the nitrogen radicalprecursor, causing dissociation of the nitrogen radical precursor intothe nitrogen radicals.

In the presence of the plasma 10, the nitrogen radicals are reactive andmay chemisorb to a surface of the substrate 2, as shown in FIG. 3.However, the nitrogen may not actually form (e.g., deposit) on thesubstrate 2 at this point in the process. The energy 8 may be turnedoff, terminating the plasma. The reactor may then be purged, such aswith another purge gas 12 that includes, for example, the nitrogenradical precursor and the rate-enhancing gas (if present). In theabsence of the plasma 10, the purge gas may be substantiallynon-reactive. During the purge, the nitrogen radicals remain absorbed tothe substrate 2. The purge may be conducted for an amount of timeranging from about 0.1 second to about 50 seconds. Thus, the nitrogenradicals may function as a source of nitrogen in the silicon-containingdielectric material. By utilizing the helium or other rate-enhancing gasto form the nitrogen radicals, nitrogen may be incorporated into thesilicon-containing dielectric material without generating hydrogen,which would damage other components of the semiconductor device.

As shown in FIG. 4, a silicon-containing precursor or asilicon-containing precursor and a carbon-containing precursor,depending on the silicon-containing dielectric material to be formed,may be introduced into the reactor following the purge. A reactant gas14 including the silicon-containing precursor and the carbon-containingprecursor (if present) may be introduced into the chamber. Thesilicon-containing precursor may include, but is not limited to, silane(SiH₄), tetraethylorthosilicate (TEOS), trisilylamine (TSA),tetramethylcyclotetrasiloxane (TOMCAT), or combinations thereof. In oneembodiment, the silicon-containing precursor is silane. However, otherconventional silicon-containing precursors may be used. Thecarbon-containing precursor may include, but is not limited to,trimethyl silane (TMS), an alkyl amine, acetylene, propylene, orcombinations thereof. In one embodiment, the carbon-containing precursoris TMS. However, other conventional carbon-containing precursors may beused. The silicon-containing precursor and the carbon-containingprecursor (if present) may be selected depending on thesilicon-containing dielectric material to be formed. Thesilicon-containing precursor and the carbon-containing precursor may beintroduced separately or as a mixture depending on the desired contentof silicon and carbon in the resulting silicon-containing dielectricmaterial. In one embodiment, a mixture of TMS and silane is used toprovide an increased deposition rate of the silicon and carbonmonolayers. The substrate 2 having the nitrogen chemisorbed to itssurface may be exposed to the silicon-containing precursor and thecarbon-containing precursor (if present) so that silicon monolayers andcarbon monolayers are formed and bonded to the nitrogen. Thesilicon-containing precursor and the carbon-containing precursor (ifpresent) may be flowed for an amount of time ranging from about 1 secondto about 50 seconds.

To reduce or prevent overheating of the substrate 2 during the plasmaprocess, the pressure of the chamber may be increased during exposure ofthe substrate 2 to the silicon-containing precursor or thesilicon-containing precursor and the carbon-containing precursor. Thepressure in the chamber may be increased from its initial state (atabout 2 Torr), such as by controlling a pressure control valve. Thepressure may be increased to from about 6 Torr to about 12 Torr, such asabout 8 Torr. In addition, a thermally conductive gas, such as helium,argon, or hydrogen, may be introduced into the chamber to control thetemperature of the substrate 2. The thermally conductive gas mayincrease conduction away from the substrate 2, lowering the temperatureof the substrate 2. The thermally conductive gas and the increasedpressure in the chamber may also be used at other stages during theformation of the silicon-containing dielectric material to reduce orprevent overheating of the substrate 2.

The plasma 10 may be cycled on and off during formation of thesilicon-containing dielectric material. The plasma 10 may be turned onwhile the substrate 2 is exposed to the nitrogen radical precursor andrate-enhancing gas (if present), following which the plasma 10 may beturned off before the substrate 2 is exposed to the silicon-containingprecursor and the carbon-containing precursor (if present). Thus, only aportion of the process of the present disclosure is conducted in thepresence of the plasma 10. Since the plasma contains the nitrogenradical precursor and the oxygen-containing precursor (if present) andis free of ammonia or an amine, no hydrogen-containing species areproduced that may potentially damage already-formed materials on thesubstrate 2. While hydrogen may be present in the silicon-containingprecursor and the carbon-containing precursor (if present), reactivehydrogen species are not produced because no plasma 10 is present atthis stage of the process.

By conducting multiple cycles of exposure to the elemental nitrogen,oxygen-containing precursor (if present), silicon-containing precursor,and carbon-containing precursor (if present), the silicon-containingdielectric material 16 (i.e., silicon carbon nitride material) may beformed on the substrate 2, as shown in FIG. 5. The silicon-containingdielectric material 16 may be formed at a rate of from about 10 Å/min toabout 500 Å/min and to a thickness within a range of from about 10 Å toabout 1000 Å.

While the embodiments of the disclosure as described above andillustrated in FIGS. 1-5 produce SiCN_(y) as the silicon-containingdielectric material 16 (using elemental nitrogen, helium, thesilicon-containing precursor, and the carbon-containing precursor), thehelium is optional and is used to increase a rate at which thesilicon-containing dielectric material 16 is formed. However, the plasmaportion of the process may be conducted without (i.e., in the absenceof) helium or other rate-enhancing gas. In addition, if thesilicon-containing dielectric material 16 is to include oxygen, theoxygen-containing precursor may be introduced with the elementalnitrogen and the rate-enhancing gas (if present), during the plasmaportion of the process. If the silicon-containing dielectric material 16is to include carbon, the carbon-containing precursor may be introducedwith the silicon-containing precursor, i.e., during the non-plasmaportion of the process.

While embodiments of the present disclosure describe the nitrogenradical precursor as being elemental nitrogen, nitrous oxide (N₂O) maybe used instead of elemental nitrogen. When energy 8 to form such aplasma 10 is applied, the N₂O may dissociate into the nitrogen radicals,as described above for the elemental nitrogen.

For formation of SiN_(y) or SiCN_(y), the nitrogen radicals are reactiveand may chemisorb to a surface of the substrate 2 as shown in FIG. 2.If, however, the silicon-containing dielectric material 16 to be formedis SiO_(x) or SiC_(x)O_(y), the oxygen-containing precursor (not shown)may be present in the plasma 10. The oxygen-containing precursor may beoxygen (O₂), water (H₂O), nitrous oxide (N₂O), carbon dioxide (CO₂), orcombinations thereof. The oxygen-containing precursor may be introducedin gaseous form into the chamber with the nitrogen radical precursor andrate-enhancing gas (if present). The oxygen-containing precursor mayform an oxygen monolayer on the surface of the substrate 2 while thenitrogen radicals of the nitrogen radical precursor function to reducespreading of the plasma. If the oxygen-containing precursor is present,the oxygen-containing precursor may be more reactive than the nitrogenradicals so that oxygen chemisorbs to the surface of the substrate 2.

Accordingly, the present disclosure includes a method of foil ling asilicon-containing dielectric material that comprises forming a plasmacomprising nitrogen radicals, absorbing the nitrogen radicals onto asubstrate, and exposing the substrate to a silicon-containing precursorin a non-plasma environment to form monolayers of a silicon-containingdielectric material on the substrate.

The present disclosure also includes a method of forming asilicon-containing dielectric material that comprises forming a plasmacomprising nitrogen radicals and oxygen radicals, exposing a substrateto the plasma to absorb oxygen onto the substrate, and exposing thesubstrate to a silicon-containing precursor to form monolayers of asilicon-containing dielectric material on the substrate.

While embodiments of the present disclosure describe the rate-enhancinggas as helium, the rate-enhancing gas may be ammonia (NH₃) or hydrogen(H₂) if underlying materials are not damaged by hydrogen, which would beproduced during the plasma portion of the process. Ammonia may also beused as the rate-enhancing gas when additional nitrogen content in theresulting silicon-containing dielectric material is desired.

The composition of the silicon-containing dielectric material 16 formedon the substrate 2 may vary depending on the ratio of elementalnitrogen, oxygen-containing precursor (if present), silicon-containingprecursor, and the carbon-containing precursor (if present) used. Forinstance, the carbon and silicon content of the silicon-containingdielectric material 16 may depend on the ratio of silicon-containingprecursor and carbon-containing precursor used during the process. If ahigher silicon content is desired, a higher flow rate of thesilicon-containing precursor may be used or a carbon-containingprecursor containing both silicon and carbon (i.e., TMS) may be used. Ifa higher carbon content is desired, a higher flow rate of thecarbon-containing precursor may be used.

The silicon-containing dielectric material 16 may include astoichiometric or non-stoichiometric composition of the silicon oxide,the silicon carbon oxide, the silicon nitride, or the silicon carbonnitride. By way of example, the silicon oxide may be SiO or SiO₂, thesilicon carbon oxide may include from about 30% to about 70% silicon,from about 4% to about 25% carbon, and from about 5% to about 66%oxygen, a silicon nitride may include from about 10% to about 90%silicon and from about 10% to about 90% nitrogen, and a silicon carbonnitride may include from about 30% to about 70% silicon, from about 4%to about 25% carbon, and from about 5% to about 66% nitrogen. In oneembodiment, the silicon carbon nitride includes about 50% silicon, about20% carbon, and about 30% nitrogen.

Examples of reactants for forming silicon oxide (SiO_(x)), siliconcarbon oxide (SiC_(x)O_(y)) silicon nitride (SiN_(y)), and siliconcarbon nitride (SiC_(x)N_(y)) are shown in Table 1. To form therespective silicon-containing dielectric materials 16, a portion of theprocess is conducted in a plasma environment and a portion of theprocess is conducted in a non-plasma environment, as previouslydescribed in reference to FIGS. 1-5.

TABLE 1 Reactants used in Material to be Plasma Reactants used in Non-formed Environment plasma Environment SiO_(x) N₂O + N₂ SiH₄ SiC_(x)O_(y)CO₂ + N₂ TMS + SiH₄ SiN_(y) N₂ SiH₄ SiC_(x)N_(y) N₂ TMS TMS + SiH₄SiC_(x)N_(y) TSA TSA

During the formation of SiO, or SiC_(x)O_(y), the N₂O or CO₂ in theplasma environment, respectively, function as the oxygen-containingprecursor. The N₂ in the plasma reduces spreading of the plasma.Although nitrogen is present in the plasma along with oxygen, verylittle nitrogen is incorporated into the SiO_(x) or SiC_(x)O_(y) becausethe oxygen is significantly more reactive than the nitrogen. During theformation of the SiN_(y) or SiC_(x)N_(y), the N₂ functions as thenitrogen source and is incorporated into the silicon-containingdielectric material.

During the formation of SiO_(x) or SiN_(y), the SiH₄ in the non-plasmaenvironment functions as the silicon source. During the formation ofSiC_(x)O_(y) or SiC_(x)N_(y), the SiH₄ and TMS in the non-plasmaenvironment function as the silicon source and the TMS functions as thecarbon source.

Additional embodiments for forming silicon oxide (SiO_(x)), siliconcarbon oxide (SiCO_(x)) silicon nitride (SiN_(y)), and silicon carbonnitride (SiCN_(y)) are shown in Table 2, which includes the presence ofhelium in the plasma environment.

TABLE 2 Material to be formed Plasma Environment Non-plasma EnvironmentSiO₂ N₂O + N₂ + He (optional) SiH₄ + N₂ SiC_(x)O_(y) CO₂ + N₂ + He(optional) TMS + SiH₄ (optional) + N₂ SiN_(y) N₂ + He (optional) + NH₃SiH₄ + He (optional) + N₂ (optional) SiC_(x)N_(y) N₂ + He (optional) +NH₃ TMS + N₂ + SiH₄ (optional) + (optional) He (optional)

Since the formation of the silicon-containing dielectric material 16 isconducted at a low temperature, damage done to existing components ormaterials on the substrate 2 may be reduced. Thus, the process of thepresent disclosure may be used to form the silicon-containing dielectricmaterial in any application where materials susceptible to damage, suchas volatilization or evaporation of the material, are already formed onthe substrate 2. For instance, carbon materials and exotic materials mayalready be present on the substrate 2 before the silicon-containingdielectric material 16 is formed according to an embodiment of thepresent disclosure. The silicon-containing dielectric material 16 mayalso improve adhesion to other materials, such as underlying materialsor overlying materials. In addition, the silicon-containing dielectricmaterial 16 may function as a barrier to diffusion or evaporation of theunderlying materials, and may also provide physical containment of theunderlying materials. The silicon-containing dielectric material 16 mayprevent or reduce diffusion of ions between neighboring materials, suchas between a gate material and an electrode material. Thesilicon-containing dielectric material 16 may also prevent oxygen orwater in the environment from diffusing through the silicon-containingdielectric material 16. The formation of the silicon-containingdielectric material may also reduce or prevent chamber contamination bysealing underlying materials as the substrate heats up.

Thus, in addition to being electrically insulative, thesilicon-containing dielectric material 16 may function as a diffusionbarrier, may provide improved adhesion between adjacent materials, maypassivate underlying materials, or may encapsulate underlying materials.

The silicon-containing dielectric materials 16 formed as described abovemay exhibit improved electrical properties, such as low leakage and ahigh breakdown voltage, compared to materials formed by conventional CVDand ALD techniques at the same temperature range. Additionally, if thesilicon-containing dielectric material 16 contains carbon, thesilicon-containing dielectric material 16 may have a reduced dielectricconstant (k). For silicon-containing dielectric materials 16 thatinclude carbon, the wet etch rate may also be low, providing goodselectivity to other materials.

The silicon-containing dielectric material 16 may be used in asemiconductor device structure. By way of example and as shown in FIG.6, the silicon-containing dielectric material 16 may be formed on astack 18. The stack 18 may include different components formed ofvarious materials depending on its intended use, such as in memoryapplications. By way of example, the stack 18 may be used innon-volatile memory applications including, but not limited to, NANDflash memory or phase-change memory. By way of example, the stack 18 mayinclude tungsten 20, a first electrode 22, a first chalcogenide material24, a second electrode 26, a second chalcogenide material 28, and athird electrode 30. The first chalcogenide material 24 and the secondchalcogenide material 28 may include chalcogenide materials havingdifferent compositions. The first, second, and third electrodes 22, 26,30 may be formed from carbon. The stacks 18 may be formed byconventional techniques, which are not described in detail herein. Thesilicon-containing dielectric material 16 may be formed over stacks 18separated by a distance W. The silicon-containing dielectric material 16may be formed over the stacks 18 according to an embodiment of thepresent disclosure. In one embodiment, the silicon-containing dielectricmaterial 16 is SiC_(x)N_(y). Since the SiC_(x)N_(y) includes carbon, thefirst silicon-containing dielectric material 16 may sufficiently adhereto the first, second, and third electrodes 22, 26, 30, which alsoinclude carbon. Additionally, since the formation of the SiC_(x)N_(y)occurs at a low temperature, the silicon-containing dielectric material16 may be formed without damaging the tungsten 20, the first, second,and third electrodes 22, 26, 30, and the first and second chalcogenidematerials 24, 28. However, SiO_(x), SiN_(y), or SiC_(x)O_(y) may also beformed as the silicon-containing dielectric material 16.

Multiple silicon-containing dielectric materials 16 may also be formedon the stacks 18, as shown in FIG. 7. A first silicon-containingdielectric material 16, such as SiC_(x)N_(y), may be formed over thestack 18 according to an embodiment of the present disclosure. Since theSiC_(x)N_(y) includes carbon, the first silicon-containing dielectricmaterial 16 may adhere to the first, second, and third electrodes 22,26, 30 which also include carbon. A second silicon-containing dielectricmaterial 16′, such as one of SiO_(x), SiN_(y), or SiC_(x)O_(y), may beformed on the first silicon-containing dielectric material 16. In oneembodiment, the second silicon-containing dielectric material 16′ isSiN_(y). The second silicon-containing dielectric material 16′ may beformed according to an embodiment of the present disclosure. A thirdsilicon-containing dielectric material 16″, such as another of SiO_(x),SiN_(y), or SiC_(x)O_(y), may be formed on the second silicon-containingdielectric material 16′. In one embodiment, the third silicon-containingdielectric material 16″ is SiC_(x)O_(y). The third silicon-containingdielectric material 16″ may be formed according to an embodiment of thepresent disclosure. While SiC_(x)N_(y) is described as being formeddirectly on the stack 18, the first, second, and thirdsilicon-containing dielectric materials 16, 16′, 16″ may be formed fromSiC_(x)N_(y), SiO_(x), SiN_(y), or SiC_(x)O_(y) in any order dependingon the intended use of the stack 18.

Since the silicon-containing dielectric materials 16 are formed by aPEALD process, the methods of the present disclosure may be used to formthe silicon-containing dielectric materials 16 on closely spacedadjacent stacks 18, such as stacks 18 separated by a distance W, such asbetween about 50 Å and about 220 Å or between about 180 Å and about 200Å. Conventional processes, such as CVD processes, of forming thesilicon-containing dielectric materials 16 are not capable of formingthe materials on such closely-spaced stacks 18. In addition,conventional ALD processes are not capable of forming the materialswithout damaging portions of the stacks 18, such as portions formed ofchalcogenide materials or carbon materials.

Accordingly, the present disclosure includes a semiconductor devicestructure that comprises stacks and at least one conformalsilicon-containing dielectric material on each of the stacks. The stacksare separated from one another by a distance of from about 50 Å to about220 Å.

The present disclosure also includes a method of forming a semiconductordevice structure that comprises forming stacks comprising tungsten, atleast one electrode, and at least one chalcogenide material. At leastone silicon-containing dielectric material is conformally formed on eachof the stacks by forming a plasma comprising nitrogen radicals,absorbing nitrogen from the plasma onto a substrate, terminating theplasma, and exposing the substrate to a silicon-containing precursor ina non-plasma environment to form monolayers of the at least onesilicon-containing dielectric material on the substrate.

While the disclosure is susceptible to various modifications andalternative forms, specific embodiments have been shown by way ofexample in the drawings and have been described in detail herein.However, the disclosure is not intended to be limited to the particularforms disclosed. Rather, the disclosure is to cover all modifications,equivalents, and alternatives falling within the scope of the disclosureas defined by the following appended claims and their legal equivalents.

What is claimed is:
 1. A method of forming a silicon-containing dielectric material, comprising: forming a plasma comprising nitrogen radicals; absorbing the nitrogen radicals onto a substrate; and exposing the substrate to a silicon-containing precursor in a non-plasma environment to form monolayers of a silicon-containing dielectric material on the substrate.
 2. The method of claim 1, wherein forming a plasma comprising nitrogen radicals comprises dissociating a nitrogen radical precursor into the nitrogen radicals.
 3. The method of claim 2, wherein dissociating a nitrogen radical precursor into the nitrogen radicals comprises dissociating a nitrogen radical precursor selected from the group consisting of elemental nitrogen, nitrous oxide, ammonia, nitrogen oxide, azide, an azide derivative, dinitrogen pentoxide, hydrazine, and a hydrazine derivative into the nitrogen radicals.
 4. The method of claim 1, wherein forming a plasma comprising nitrogen radicals comprises forming the plasma comprising the nitrogen radicals and helium.
 5. The method of claim 1, wherein absorbing the nitrogen radicals onto a substrate and exposing the substrate to a silicon-containing precursor in a non-plasma environment comprises forming monolayers of nitrogen and silicon as the substrate is heated.
 6. The method of claim 1, wherein exposing the substrate to a silicon-containing precursor comprises exposing the substrate to silane to form monolayers of silicon on the substrate.
 7. The method of claim 1, wherein exposing the substrate to a silicon-containing precursor comprises exposing the substrate to trimethylsilane and silane to form monolayers of carbon and silicon on the substrate.
 8. The method of claim 1, further comprising repeating the acts of forming the plasma comprising nitrogen radicals, absorbing the nitrogen radicals onto the substrate, and exposing the substrate to the silicon-containing precursor to form the silicon-containing dielectric material at a desired thickness.
 9. The method of claim 1, wherein forming a plasma comprising nitrogen radicals, absorbing the nitrogen radicals onto a substrate, and exposing the substrate to a silicon-containing precursor in a non-plasma environment are conducted at a temperature between about 20° C. and about 300° C.
 10. The method of claim 1, further comprising reducing a pressure of a chamber in which the silicon-containing dielectric material is faulted while the substrate is exposed to the silicon-containing precursor.
 11. A method of forming a silicon-containing dielectric material, comprising: forming a plasma comprising nitrogen radicals and oxygen radicals; exposing a substrate to the plasma to absorb oxygen onto the substrate; and exposing the substrate to a silicon-containing precursor to form monolayers of a silicon-containing dielectric material on the substrate.
 12. The method of claim 11, wherein forming a plasma comprising nitrogen radicals and oxygen radicals comprises forming a plasma from elemental nitrogen and nitrous oxide or elemental nitrogen and carbon dioxide.
 13. The method of claim 11, wherein forming a plasma comprising nitrogen radicals and oxygen radicals comprises forming the plasma from elemental nitrogen, an oxygen-containing precursor, and helium.
 14. The method of claim 11, wherein forming a plasma comprising nitrogen radicals and oxygen radicals comprises forming the plasma from elemental nitrogen and nitrous oxide and wherein exposing the substrate to a silicon-containing precursor comprises exposing the substrate to silane to form silicon dioxide.
 15. The method of claim 11, wherein forming a plasma comprising nitrogen radicals and oxygen radicals comprises forming the plasma from elemental nitrogen and carbon dioxide and wherein exposing the substrate to a silicon-containing precursor comprises exposing the substrate to trimethylsilane to form silicon carbon oxide.
 16. The method of claim 11, wherein exposing the substrate to a silicon-containing precursor comprises exposing the substrate to the silicon-containing precursor in a non-plasma environment.
 17. The method of claim 11, wherein exposing the substrate to a silicon-containing precursor comprises exposing the substrate to trimethylsilane or silane.
 18. The method of claim 11, further comprising repeating the acts of forming the plasma comprising nitrogen radicals and oxygen radicals, exposing the substrate to the plasma to absorb oxygen onto the substrate, and exposing the substrate to the silicon-containing precursor to form monolayers of the silicon-containing dielectric material at a desired thickness.
 19. A semiconductor device structure comprising: stacks separated from one another by a distance of from about 50 Å to about 220 Å; and at least one conformal silicon-containing dielectric material on each of the stacks.
 20. The semiconductor device structure of claim 19, wherein the at least one conformal silicon-containing dielectric material comprises at least one of a silicon oxide material, a silicon nitride material, a silicon carbon nitride material, and a silicon carbon oxide material.
 21. The semiconductor device structure of claim 19, wherein each of the stacks comprises tungsten, a first electrode on the tungsten, a first chalcogenide material on the first electrode, a second electrode on the first chalcogenide material, a second chalcogenide material on the second electrode, and a third electrode on the second chalcogenide material.
 22. The semiconductor device structure of claim 19, wherein each stack comprises a silicon carbon nitride material in contact with the tungsten, first electrode, first chalcogenide material, second electrode, second chalcogenide material and third electrode of the stack.
 23. A method of forming a semiconductor device structure comprising: forming stacks comprising tungsten, at least one electrode, and at least one chalcogenide material; and conformally forming at least one silicon-containing dielectric material on each of the stacks, comprising: forming a plasma comprising nitrogen radicals; absorbing nitrogen from the plasma onto a substrate; terminating the plasma; and exposing the substrate to a silicon-containing precursor in a non-plasma environment to form monolayers of the at least one silicon-containing dielectric material on the substrate.
 24. The method of claim 23, further comprising repeating the acts of absorbing nitrogen from the plasma onto the substrate, terminating the plasma, and exposing the substrate to the silicon-containing precursor to form the at least one silicon-containing dielectric material at a desired thickness. 